Elsevier

The Journal of Pediatrics

Volume 198, July 2018, Pages 234-239.e1
The Journal of Pediatrics

Original Articles
A Brain Marker for Developmental Speech Disorders

https://doi.org/10.1016/j.jpeds.2018.02.043Get rights and content

Objective

To characterize the organization of speech- and language-related white matter tracts in children with developmental speech and/or language disorders.

Study design

We collected magnetic resonance diffusion-weighted imaging data from 41 children, ages 9-11 years, with developmental speech and/or language disorders, and compared them with 45 typically developing controls with the same age range. We used probabilistic tractography of diffusion-weighted imaging to map language (3 segments of arcuate fasciculus, extreme capsule system) and speech motor (corticobulbar) tracts bilaterally. The corticospinal and callosal tracts were used as control regions. We compared the mean fractional anisotropy and diffusivity values between atypical and control groups, covarying for nonverbal IQ. We then examined differences between atypical subgroups: developmental speech disorder (DSD), developmental language disorder, and co-occurring developmental speech and language disorder.

Results

Fractional anisotropy in the left corticobulbar tract was lower in the DSD than in the control group. Radial and mean diffusivity were higher in the DSD than the developmental language disorder, co-occurring developmental speech and language disorder, or control groups. There were no group differences for any metrics in the language or control tracts.

Conclusions

Atypical development of the left corticobulbar tract may be a neural marker for DSD. This finding is in line with reports of speech disorder after left corticobulbar damage in children and adults with brain injury. By contrast, we found no association between diffusion metrics in language-related tracts in developmental language disorder, and changes for language disorders are likely more complex.

Section snippets

Methods

Participants (n = 86; age range, 9.25-11.25 years) were recruited from the Early Language in Victoria Study (ELVS), a longitudinal community-based study of 1900 children.3 Communication status was collected almost annually from 8 to 10 months of age3 up to the age at the current study (ie, 9-11 years). Age of scanning was carefully chosen to reflect a time when communication trajectories are relatively stable.17 Ethics approval was granted by the Royal Children's Hospital Human Research Ethics

Results

The 4 groups were matched for demographic characteristics (Table I). Male:female were comparable across groups (DSD, 7:10; DSLD, 6:5; DLD, 7:6; control, 21:24). Nonverbal IQ scores, although within the typical range, were lower in children with DLD than in children with DSD as commonly reported in this group.17 As expected, children with DLD had significantly lower CELF-IV scores (total, receptive, and expressive) than the other 2 groups, whereas children with DSD had significantly lower

Discussion

We report herein an association between DSD and reduced fractional anisotropy of the left CBT, suggesting that atypical development of this tract may be a neural marker for DSD. Altered connectivity of the left CBT has previously been associated with speech disorder in different childhood populations and disease models, including childhood stuttering14 and dysarthria after childhood traumatic brain injury.13 In adult cases, left hemisphere lesions to regions along the CBT as tracked here (ie,

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  • Cited by (0)

    Supported by the National Health and Medical Research Council (NHMRC) Centre of Research Excellence (CRE) (1023493 [to S.R., A.M., and A.C.]); NHMRC CRE (1116976 [to A.M., A.C., and S.R.]); NHMRC Career Development Fellowship (607315 [to A.M.]) and NHMRC Practitioner Fellowship (1105008 [to A.M.]); and a Hearing CRC grant (to S.R., A.M.) A.M., S.R., and A.C. are grateful to the Operational Infrastructure Support Program of the State Government of Victoria for their support. The authors declare no conflicts of interest.

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